A fluorescent aptasensor based on nitrogen-doped carbon supported palladium and exonuclease III-assisted signal amplification for sensitive detection of AFB.

Aflatoxin B1 (AFB) has strong carcinogenicity and toxicity, so it is necessary to develop a highly sensitive detection method. In this paper, a novel nitrogen-doped carbon supported palladium (C-N-Pd) material was synthesized and firstly used as the energy receptor for fluorescent aptasensor. Using C-N-Pd as a novel quenching material and exonuclease Ⅲ (Exo III) as assisted signal amplification, a fluorescent aptasensor for AFB detection was constructed. Compared with the sensor without enzyme, the fluorescence intensity obtained by the sensor with Exo III increased by 74.7%. The fabricated fluorescent aptasensor exhibited a good selectivity toward AFB with a limit of detection (LOD) as low as 9 pg mL. Moreover, the designed aptasensor was successfully utilized to detect AFB in spiked corn, peanut and wine samples, and the LOD is 15 pg mL, 13 pg mL and 18 pg mL, respectively. In addition, the aptasensor was also compared with HPLC method, and the good agreement was found between them.